As is known, the rubber mixtures employed in production of the various tyre parts entail the use of anti-ageing agents to prevent deterioration of the rubber due to the reaction of the polymer base with oxygen and/or ozone.
The anti-ageing agents are materials added to the compounds subject to oxidation, such as the polymers, in order to inhibit or slow down the oxidative processes (since they themselves are oxidised). In other words, the anti-ageing agents are materials able to react with the atmospheric agents, preventing the latter reacting with the polymer base.
The concentration in the mixture of the anti-ageing agents depends on the level of exposure to the atmosphere and on the temperature and mechanical stress to which the specific tyre portion to which the mixture refers is subject.
The anti-ageing agents most commonly used belong to the family of the paraphenylenediamines (PPD), for example N-1,3-dimethylbutyl-N′-phenyl-paraphenylenediamine (6PPD), N,N′-diphenyl-p-phenylenediamine (DPPD), or they can be phenol derivatives such as 2,6-Di-tert-butyl-4-methylphenol (BHT), or to the family of the quinolines, for example poly(1,2-dihydro-2,2,4-trimethylquinoline) (TMQ).
During its research, the Applicant found a new class of anti-ageing agents which are able to constitute a valid alternative to the known anti-ageing agents.